- Synthesis of osthol-based botanical fungicides and their antifungal application in crop protection
-
Plant pathogenic fungi decrease the quality and productivity of plant production. The botanical fungicides have better biocompatibility and rapid biodegradation, little or no cross resistance, and the structural diversity, and thus are beneficial to deal with plant fungal diseases. Osthole has been widely used as the commercial botanical fungicide against powdery mildew in China. In this article, a series of osthole derivatives were synthesized, which respectively contain different substituents on the benzene ring, at the C8-position and pyrone ring. All the target compounds were evaluated in vitro for their antifungal activity against resistant phytopathogenic fungi. Colletotrichum fragariae, Strawberry Botrytis Cinerea, Kiwifruit Botrytis Cinerea, Kiwifruit brown Rots, which are common in fruit fungal diseases. The compound C4 was identified as the most promising candidate with the EC50 values at 38.7 μg/mL against Colletotrichum Fragariae, 14.5 μg/mL against Strawberry Botrytis Cinerea and 24.3 μg/mL against Kiwifruit Botrytis Cinerea, respectively, whereas the antifungal activity against resistant phytopathogenic fungi. of osthole is too low to be used (EC50 > 400 ppm). The results of mycelial relative conductivity determination, PI uptake and fluorescence spectroscopy indicated that the cell membrane of fungi is the key action site of C4. Besides, C4 has the potent inhibitory activity against both of plant and human pathogenic bacteria. Our studies showed that C4 was worthy for further attention as a promising botanical fungicide candidate in crop protection.
- Guo, Yuying,Chen, Jiabao,Ren, Dan,Du, Bo,Wu, Lei,Zhang, Yuanyuan,Wang, Zhouyu,Qian, Shan
-
-
- Osthole derivatives and preparation method and application thereof
-
The invention relates to osthole derivatives, and a preparation method and application thereof, and belongs to the technical field of organic chemistry. The technical problem to be solved by the present invention is to provide the novel osthole derivatives. The isopentene group on the No.8 site of osthole is modified and transformed to obtain a series of the osthole derivatives having bacteriostatic effects, and the structures of the derivatives are shown as a formula I. The derivatives are chemically synthesized from 7-hydroxycoumarin with a simple preparation process and a high yield, and the obtained products have good bacteriostatic effects, and can be used for plant disease control, especially for control of plant anthracnose, late blight, brown speckle disease or gray mold.
- -
-
Paragraph 0057-0059
(2019/11/13)
-
- Half-Sandwich Ruthenium Carbene Complexes Link trans-Hydrogenation and gem-Hydrogenation of Internal Alkynes
-
The hydrogenation of internal alkynes with [Cp?Ru]-based catalysts is distinguished by an unorthodox stereochemical course in that E-alkenes are formed by trans-delivery of the two H atoms of H2. A combined experimental and computational study now provides a comprehensive mechanistic picture: a metallacyclopropene (??2-vinyl complex) is primarily formed, which either evolves into the E-alkene via a concerted process or reacts to give a half-sandwich ruthenium carbene; in this case, one of the C atoms of the starting alkyne is converted into a methylene group. This transformation represents a formal gem-hydrogenation of a ?€-bond, which has hardly any precedent. The barriers for trans-hydrogenation and gem-hydrogenation are similar: whereas DFT predicts a preference for trans-hydrogenation, CCSD(T) finds gem-hydrogenation slightly more facile. The carbene, once formed, will bind a second H2 molecule and evolve to the desired E-alkene, a positional alkene isomer or the corresponding alkane; this associative pathway explains why double bond isomerization and over-reduction compete with trans-hydrogenation. The computed scenario concurs with para-hydrogen-induced polarization transfer (PHIP) NMR data, which confirm direct trans-delivery of H2, the formation of carbene intermediates by gem-hydrogenation, and their evolution into product and side products alike. Propargylic aOR (R = H, Me) groups exert a strong directing and stabilizing effect, such that several carbene intermediates could be isolated and characterized by X-ray diffraction. The gathered information spurred significant preparative advances: specifically, highly selective trans-hydrogenations of propargylic alcohols are reported, which are compatible with many other reducible functional groups. Moreover, the ability to generate metal carbenes by gem-hydrogenation paved the way for noncanonical hydrogenative cyclopropanations, ring expansions, and cycloadditions.
- Guthertz, Alexandre,Leutzsch, Markus,Wolf, Lawrence M.,Gupta, Puneet,Rummelt, Stephan M.,Goddard, Richard,Farès, Christophe,Thiel, Walter,Fürstner, Alois
-
supporting information
p. 3156 - 3169
(2018/03/08)
-
- Synthesis of osthole derivatives with grignard reagents and their larvicidal activities on mosquitoes
-
The structure of osthole has been modified to improve its larvicidal activity against mosquitoes. A new efficient synthesis of osthole derivatives with Grignard reagents has been developed, which employs CuI and LiCl as promoters and covers a broad range of substrates to afford the corresponding products in mild to good yields (up to 83%). Bio-activity evaluation showed that several products exhibited better activities than osthole. CuI and LiCl promoted efficient synthesis of osthole derivatives with Grignard reagents has been developed. Bio-activity evaluation showed that several products exhibited far better larvicidal activities against mosquitoes than osthole.
- Liu, Ming,Liu, Yang,Hua, Xuewen,Wu, Changchun,Zhou, Sha,Wang, Baolei,Li, Zhengming
-
supporting information
p. 1353 - 1358
(2016/02/18)
-
- Palladium-catalyzed synthesis of 8-allyl or 8-prenylcoumarins by using organotin reagents as multicoupling nucleophiles
-
In this study, 8-iodocoumarin derivatives underwent a direct Stille cross-coupling reaction with several organotin compounds in the presence of a catalytic amount of Pd(PPh3)4 in DMF at 80 °C. The cross-coupling reaction proceeded smoothly under mild conditions and permitted the formation of 8-allyl or 8-prenylcoumarin compounds in good yields. Copyright
- Yin, Qiang,Yan, Han,Zhang, Yaqin,Wang, Yige,Zhang, Guojin,He, Yuxiang,Zhang, Weihua
-
-
- Pancreatic anticancer activity of a novel geranylgeranylated coumarin derivative
-
A series of hydroxycoumarin derivatives has been synthesized and evaluated against human pancreatic PANC-1 cancer cells under nutrient-deprived conditions. Several compounds exhibited 100% preferential cytotoxicity at low micromolar concentrations under n
- Devji, Tehsina,Reddy, Claire,Woo, Christina,Awale, Suresh,Kadota, Shigetoshi,Carrico-Moniz, Dora
-
experimental part
p. 5770 - 5773
(2011/10/18)
-
- Ecofriendly iodination of activated aromatics and coumarins using potassium iodide and ammonium peroxodisulfate
-
An environmentally benign protocol for the iodination of activated aromatics, such as phenols, anilines, and hydroxycou-marins, using inexpensive commercially available potassium iodide and ammonium peroxodisulfate (1:2.5 molar equivalents per mole of substrate) in aqueous methanol (MeOH-H 2O, 6:1) at room temperature has been developed. The protocol provides for ortho-selective monoiodination as the predominant product without added acid and it is compatible with a number of common oxidizible functional groups, such as formyl, benzylic C-H, aromatic amines and hydroxymethyl. Good to acceptable yields of monoiodinated products in acceptable reaction times and exclusive ortho-iodination for 7-hydroxycoumarins, despite the presence of vinylogous electronrich C3, are some of the key advantageous features of the method. Georg Thieme Verlag Stuttgart.
- Ganguly, Nemai C.,Barik, Sujoy Kumar,Dutta, Sanjoy
-
experimental part
p. 1467 - 1472
(2010/09/16)
-
- Mild and efficient deprotection of allyl ethers of phenols and hydroxycoumarins using a palladium on charcoal catalyst and ammonium formate
-
An efficient procedure for the cleavage of allyl phenyl ethers and allyl coumarinyl ethers using a catalytic amount of 10% Pd/C in combination with ammonium formate is described. Allyl ethers of phenols are deprotected in preference to those of alcohols and this method is compatible with several reducible functional groups such as CHO, COCH3, CO2Et and NHCOCH3.
- Ganguly, Nemai C.,Dutta, Sanjoy,Datta, Mrityunjoy
-
p. 5807 - 5810
(2007/10/03)
-
- Synthesis and anti-inflammatory activity of natural and semisynthetic geranyloxycoumarins
-
Nine new 7-geranyloxycoumarin derivatives differently substituted at position 8 were semi-synthesised. Their topical anti-inflammatory activity was evaluated using the Croton oil ear test in mice as a model of acute inflammation. Auraptene (7-geranyloxycoumarin), its 8-methoxy (collinin, 1) and 8-acetoxy derivatives (5) (1μmol/cm2) provoked 50% oedema reduction, similarly to 0.25μmol/cm2 of the reference drug indomethacin, a nonsteroidal anti-inflammatory drug.
- Curini, Massimo,Epifano, Francesco,Maltese, Federica,Marcotullio, Maria C.,Tubaro, Aurelia,Altinier, Gianmario,Gonzales, Sylvia Prieto,Rodriguez, Juan C.
-
p. 2241 - 2243
(2007/10/03)
-
- A route to the structure proposed for puetuberosanol and approaches to the natural products marshrin and phebalosin
-
Synthesis of the structure claimed for puetuberosanol 1 (using the Juliá-Colonna oxidation in a key step) showed that the natural product was a different material. The isomeric epoxy alcohols 16-18 can be discounted from the alternatives. An analogue 19 of marshrin 2 was prepared but the synthesis of the natural product was thwarted by failure of a Juliá-Colonna oxidation in the key step. The epoxy ketone 29 was prepared by Darzens condensation and was converted into (±)-phebalosin 3.
- Gillmore, Adam,Lauret, Christelle,Roberts, Stanley M.
-
p. 4363 - 4375
(2007/10/03)
-
- Antioxidant properties of anthocyanins and tannins: A mechanistic investigation with catechin and the 3′,4′,7-trihydroxyflavylium ion
-
Plant polyphenols act as antioxidants mainly by trapping reactive oxygen species and by regenerating endogenous membrane-bound α-tocopherol (vitamin E). In both processes polyphenols are oxidized. Hence, knowledge of the oxidation mechanisms of polyphenols is important for an understanding of their antioxidant activity at the molecular level. This work focuses on anthocyanins (pigments) and flavanols (tannins), two important classes of polyphenols which are both relatively abundant in human diet. The oxidation of the 3′,4′,7-trihydroxyflavylium ion (1) and catechin (2), respectively taken as models for anthocyanins and tannins, has been investigated. From kinetic data and partial product analysis, the mechanisms for the reactions of 1 and 2 with sodium periodate and DPPH, a H atom-abstracting radical, are proposed. Both polyphenols are shown to form o-quinone intermediates upon H atom abstraction and subsequent radical disproportionation. In the case of 2, the quinone and a second molecule of antioxidant quickly couple to form dimers. By contrast, 1 is extensively degraded into coumarins by repeating sequences of oxidation-solvent addition, which consume several equivalents of oxidants. In aqueous solutions, 1 is typically a mixture of coloured and colourless forms. The latter (chalcones) are also shown to take part in the antioxidant activity.
- Dangles, Olivier,Fargeix, Guillaume,Dufour, Claire
-
p. 1653 - 1663
(2007/10/03)
-
- Synthesis and antifungal activity of coumarins and angular furanocoumarins
-
Angelicin, a naturally occurring furanocoumarin, that showed antifungal activity, was considered as a lead structure for a group of synthetic coumarins. Antifungal activities of the synthesized coumarins and angelicin derivatives were reported against Can
- Sardari, Soroush,Mori, Yoki,Horita, Kiyoshi,Micetich, Ronald G.,Nishibe, Sansei,Daneshtalab, Mohsen
-
p. 1933 - 1940
(2007/10/03)
-
- Efficient and convenient synthesis of angular furanocoumarins from hydroxycoumarins
-
Angular furanocoumarins (1) were synthesized via sequential reactions of vinylation of halo-hydroxycoumarins (5 or 6) with chlorodimethylvinylsilane (8) and Pd catalyst, oxidation of Tl(NO3)3 in methanol, and treatment with acid.
- Harayama, Takashi,Nishita, Yoshitaka
-
p. 1986 - 1988
(2007/10/03)
-
- SYNTHESIS OF 3-(1',1'-DIMETHYLALLYL)COUMARINS: GRAVELLIFERONE, CHALEPIN AND RUTAMARIN
-
The 3-(1',1'-dimethylallyl)coumarins chalepin (2), rutamarin (3) and gravelliferone (4) have been synthesized from umbelliferon (7) via Claisen and Cope rearrangements of 3',3'-dimethylallyl ethers of 6-(3',3'-dimethylallyl)umbelliferon with and without an iodine atom as blocking group at C-8.
- Massanet, Guillermo M.,Pando, Enrique,Rodiriquez-Luis, Francisco,Salva, Javier
-
p. 1541 - 1548
(2007/10/02)
-
- A Convenient Synthesis of Psoralen Derivatives: Psoralen, 4-Methyl-psoralen and 4-Phenyl-psoralen
-
A convenient synthesis of psoralen derivatives, viz., 7H-furo benzopyran-7-one (psoralen), 5-methyl-7H-furo benzopyran-7-one (4-methyl-psoralen) and 5-phenyl-7H-furo benzopyran-7-one (4-phenyl-psoralen) by blocking the 8-position of the starting compounds with iodine, subsequent Claisen migration followed by cyclisation is described. - Keywords: Claisen migration; Coumarins; Psoralen derivatives
- Ahluwalia, V.K.,Prakash, Chandra,Bala, Shashi
-
p. 877 - 882
(2007/10/02)
-